Analysis of avenin proteins and the expression of their mRNAs in developing oat seeds.

Abstract

We have isolated and characterized cDNA clones encoding avenins, the prolamine storage proteins of oat seeds. Sequence analysis shows that avenins are a related group of polypeptides and that their mRNAs differ from each other by point mutations and small insertions and deletions. Avenin proteins have structural homology to the a/@-gliadins and r-gliadins of wheat, the B-hordeins of barley, and the r-secalins of rye. Hybridization analysis of DNA from various diploid, tetraploid, and hexaploid oat species shows that the oat genome contains more globulin storage protein genes than avenin genes and that some restriction fragments containing these genes are conserved between species with common genomes. We estimate that there are 25 avenin genes and 50 globulin genes per haploid genome in Avena sativa and similar ratios of globulin to avenin genes in other Avena species. Avenin and globulin polypeptides begin to accumulate between 4 days and 6 days after anthesis. Messenger RNAs encoding avenin and globulin proteins become abundant 4 days after anthesis and reach peak concentrations at 8 days after anthesis. Avenin mRNAs are present in somewhat greater molar amounts than globulin mRNAs beginning at 4 days after anthesis. Because there is considerably more globulin than avenin in the mature oat seed, the expression of globulin and avenin genes may be regulated both transcriptionally and post-transcriptionally.

Diversity in oat potential immunogenicity: basis for the selection of oat varieties with no toxicity in coeliac disease

“…The spectra of the avenin fractions of the different oat varieties obtained by MALDI-TOF MS and the electrophoretic distribution of the prolamins by SDS–PAGE revealed distinct patterns that could allow their further identification (figure 2). In both MALDI-TOF MS and SDS–PAGE, the distribution of molecular weights ranged between 19 and 31 kDa, in agreement with previous work describing avenins 18 19. The number and relative intensity of the peaks obtained by MALDI-TOF MS in the nine oat cultivars were very variable, indicating that oats differ in their avenin complement.…”

Restriction fragment length polymorphism based phylogenetic analysis ofAvenaL.

“…lb) than globulin cDNA, as has already been reported by Chesnut et al (1989). Two fragments correspond to bands with an intense autoradiograph signal (4.8 and 3.8 kb).…”

“…Landry et al 1987, comparing various sources of probes for their efficiency in detecting RFLP in lettuce, concluded that an increased detection of polymorphism in multiple-copy sequences could be the result of independent mutations in the different copies of the gene in the presence of a released selection pressure. Indeed, avenin and globulin genes are known to be present in 25 and 50 copies, respectively, per haploid genome of A. sativa (Chesnut et al 1989). The present results show that the two probes hybridize with many genome sequences, and a globulin copy number reconstruction experiment confirms the large number of sequences for each fragment.…”

Mechanical and Barrier Properties of Avenin, Kafirin, and Zein Films

“…[14][15][16][17][18][19][20] Avenin is the prolamin of oats (considered the sixth most important crop globally) and has some interesting properties. Avenin resembles gluten, 21 which has displayed good mechanical material properties-gluten films can be made elastic, whereas most biopolymer materials are brittle. Another interesting aspect of avenin is that people suffering from celiac disease do not react to it, making it a more appropriate food packaging or coating material than gluten.…”